For content delivery systems, the arrangement and storage of parameters used to distribute third-party content can impact the amount of memory resources and computational resources used by such systems. Furthermore, the arrangement and storage of these parameters can influence the speed of processing requests for third-party content. Selecting and distributing third-party content items, responsive to requests for third-party content, in real time calls for efficient arrangement and storage of parameters provided by third-party content providers to manage distribution of their content to client devices.